This proposal is a revision of our parent grant R01 (DK076893) entitled, "IL-13 and Eosinophilic Esophagitis" under the auspices of notice number NOT-OD-09-058 titled: "NIH Announces the Availability for Recovery Act Funds for Competitive Revision Application." Our parent grant focuses upon IL-13 driven mechanisms of pathologic esophageal eosinophilia in epithelial cells, transgenic mice and in patients during clinical therapies. In this grant revision, entitled "Eosinophilic Esophagitis Comparative Effectiveness," we seek to integrate our molecular investigations with other clinical and pathologic outcome variables that are important in pediatric EE. In Aim 1, we will develop a local internet based registry of subjects with EE to capture defined clinical, pathologic and translational outcome measures. We will use the EE registry to test the hypothesis that esophageal mucosal eosinophil levels and identified key EE cytokines such as IL-13 correlate with defined, validated clinical outcome measurements of symptom severity and quality of life. With the development of an EE registry to capture valid, reliable and responsive outcomes, a primary goal of this proposal is to compare the efficacy of swallowed steroid medication and empiric dietary elimination on esophageal eosinophilia, symptom severity, health related quality of life and cytokine profiles. In Aim 2, we will compare the clinical effectiveness of dietary elimination to swallowed steroid medications for the treatment of pediatric EE. We will test the hypothesis that EE subjects treated with dietary elimination will have higher rates of resolution in esophageal tissue eosinophil counts and improvements in symptom severity, but will also have worsening health related quality of life as a consequence of severe dietary restriction compared to subjects treated with swallowed steroid medications. PUBLIC HEALTH RELEVANCE: The proposed aims will seek to develop a local internet based registry of subjects with EE to capture defined clinical, pathologic and translational outcome measures as a basis for comparative effectiveness investigations. Through the development of this registry we propose to compare the clinical effectiveness of dietary eliminations to swallowed steroid medications for the treatment of pediatric EE. In addition, this internet based registry has great potential to serve as a platform for future comparative effectiveness investigations across several institutions nationwide.